1. Field of the Invention
The present invention relates to a process for the preparation of triacetoxysilanes from tris(amino)silanes, and in particular, to a low temperature process for providing high yields of triacetoxysilanes from acetic anhydride and tris(amino)silanes.
2. Description of the Prior Art
Traditionally, acetoxysilanes have been prepared from the reaction of the corresponding chlorosilane (RSiCl.sub.3) with acetic acid or acetic anhydride in a batch or continuous process. Acetic acid has been generally regarded as the preferred reagent in view of its lower cost and also because hydrogen chloride is the by-product of the reaction. When acetic anhydride is employed for reaction with chlorosilane, acetyl chloride is formed, in addition to the desired acetoxysilane.
It has been reported in the the literature that mono- and di-aminosilanes react with acetic acid or acetic anhydride to give the corresponding acetoxysilanes, as, for example
1. Miner, C. S.; Bryan, L. A.; Holysz, R. P. and Pedlow, G. W.; Industr. Eng. Chem. (Industr.) 39 (1947) 1368 PA0 2. Larsson, E. Chalmers tek. Hogsk; Handl. 115 (1951) 9.
However, such references do not teach that triacetoxysilanes, such as vinyl- and ethyl triacetoxysilane, can be prepared from the reactions of triaminosilanes with acetic acid or acetic anhydride. It would have been expected, in any event, that this reaction would be difficult to carry out, since amines have been shown to react with silyl acetates to give a silicon polymer and the corresponding acetamide in U.S. Pat. No. 2,623,832, issued Dec. 30, 1952.